Turning the Prommers' area into a moshpit … Shaan at the Indian Voices Prom. Photograph: Leon Neal/AFP/Getty

Fittingly for a subcontinent of more than a billion people, the Indian Voices day at the Proms was diverse to the point of dizziness. The pair of concerts – one in the morning, one in the evening – began with venerable classical singers invoking the Hindu lord Krishna. It ended with a thirtysomething Bollywood star in a leather jacket and white jeans (kids, do not try this look at home) belting out: "All the hot girls/ Put your hands up and sing!"

Indian music has always absorbed new influences from unlikely sources, as Ram Narayan demonstrated in the morning's classical recitals. Now over 80, he has dedicated his life to rescuing the sarangi (fiddle) from its associations with courtesan culture and successfully forcing it into the classical mainstream.

Another beguiling performance followed from Rajan and Sajan Mishra, brothers who sing in a style called khyal (imagination), in which the voice itself is an instrument. It was shown off in the morning raga Lalit, where the devotional lines "Narayan, you came home/ I don't want to let you go" were repeated over and over, broken up into syllabic shards and drawn out into great vocal swoops.

"Today you've built respect for Indian music – and now I'm here to wash it off," said Shaan to begin the evening's concert. It's true that the singer's trade – he records studio tracks to which Bollywood actors can lip-synch and (crucially) thrust their pelvises – doesn't compare to India's classical traditions. Whether they borrow from reggae or hip-hop, modern Hindi film songs sound unerringly like overwrought Westlife.

The first ever Bollywood Prom, this was a commendably provocative bit of programming that attracted droves of young Asians. It was also spectacular: neon lights, a big dance troupe and the Prommers' arena turning into a moshpit. Still, one couldn't help but feel sorry for those regulars wilting in the stalls who had paid to attend a Prom but found themselves in a pop concert.